Virtual fencing may be used for protecting or securing a separation line against intrusion by unwanted persons or objects in applications where a physical fence is inadequate or impractical, such as over long distances or where the terrain is too rough, or the cost is too high. The virtual fence could be used to protect a border, or the perimeters of an enclosed security area such as an airport, a strategic site, a hospital or university campus, fields and farms, or even private houses and estates The virtual fence should provide warning about the intended intrusion, and should be able to provide information about the location and type of intrusion expected. Current solutions based on video camera imaging, and using signal processing to detect changes in those images, generally have a number of disadvantages which have limited their widespread deployment, especially for border use over long distances, or in regions where the terrain is rough. Such video systems may have high false alarm rates (FAR), limited capabilities for screening irrelevant intrusions such as by animals, significant power consumption, and they could be costly in capital expenses. A system which overcomes at least some of the disadvantages of such prior art systems and methods would therefore be advantageous.
The disclosures of each of the publications mentioned in this section and in other sections of the specification are hereby incorporated by reference, each in its entirety.